GCSE Grade - examqa.com

GCSE

AQA - Combined Science

Grade

MaterialsFor this paper you must have:

RulerPencil and RubberScientific calculator, which you are expected to use when appropriate

InstructionsAnswer all questionsAnswer questions in the space providedAll working must be shown

InformationThe marks for the questions are shown in brackets

Name:

BIOLOGY

Mark

Date:

B1 - Test 3

CELL BIOLOGY

Intermediate

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The small intestine is lined with millions of villi.The diagram shows the structure of a villus.

In the small intestine, some of the products of digestion are absorbed into the blood by activetransport.

(a) Explain what is meant by active transport.

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(2)

1.

(b) How do microvilli and mitochondria help in the active transport of the products of digestionfrom the small intestine into the blood?

Microvilli ___________________________________________________________

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Mitochondria ________________________________________________________

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(2)

(Total 4 marks)

Page 1 of 17www.examqa.com

Cells contain a solution of salts and sugars.

A student is investigating how cells change when they are put into water.

(a) The student:

• looks at a plant cell using a microscope

• adds water to the cell.

The plant cell swells up.

Explain why, as fully as you can.

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(3)

2.

(b) When animal cells are put in water, they swell up, and then burst.When plant cells are put in water, they swell up, but do not burst.

How does the structure of plant cells prevent them from bursting?

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(1)

(Total 4 marks)


The drawing shows an animal cell, seen at a very high magnification using an electronmicroscope.

3.

(a) (i) Label a mitochondrion [plural = mitochondria].

(1)

(ii) What happens in the mitochondria?

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(1)

(b) (i) Name and label the structure where you would find chromosomes.

(1)

(ii) What are chromosomes made of?

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(1)

(c) What controls the rate of chemical reactions in the cytoplasm?

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(1)

(Total 5 marks)


The diagram shows a human sperm. Inside the tail of the sperm is a filament mechanism thatcauses the side to side movement of the tail, which moves the sperm.

4.

(a) Describe the function of the mitochondria and suggest a reason why they are arrangedaround the filament near the tail of the sperm.

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(3)

(b) Explain the significance of the nucleus in determining the characteristics of the offspring.

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(2)

(Total 5 marks)


The human lung has about 80 million alveoli.The diagram shows some alveoli in a human lung.

(a) Give three features of the alveoli that allow large amounts of oxygen to enter the blood.

1. _________________________________________________________________

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2. _________________________________________________________________

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3. _________________________________________________________________

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(3)

5.

(b) (i) Name the process by which oxygen passes from the air into the blood.

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(1)

(ii) Breathing allows large amounts of oxygen to enter the blood.

Explain how breathing does this.

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(2)

(Total 6 marks)


Gas exchange takes place in the lungs.

The diagram shows an alveolus next to a blood capillary in a lung.

The arrows show the movement of two gases, A and B.

6.

(a) (i) Draw a ring around the correct answer to complete the sentence.

Gases A and B move by

diffusion.

osmosis.

respiration.

(1)

(ii) Gas A moves from the blood to the air in the lungs.

Gas A is then breathed out.

Name Gas A.

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(1)

(iii) Which cells in the blood carry Gas B?

Draw a ring around the correct answer.

platelets red blood cells white blood cells

(1)

(b) The average number of alveoli in each human lung is 280 million.

The average surface area of 1 million alveoli is 0.25 m2.

Calculate the total surface area of a human lung.

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Answer ___________________________________ m2

(2)


(c) An athlete trains to run a marathon. The surface area of each of the athlete’s lungs hasincreased to 80 m2.

Give one way in which this increase will help the athlete.

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___________________________________________________________________

(1)

(Total 6 marks)

In this question you will be assessed on using good English, organising informationclearly and using specialist terms where appropriate.

Diffusion is an important process in animals and plants.

The movement of many substances into and out of cells occurs by diffusion.

Describe why diffusion is important to animals and plants.

7.

In your answer you should refer to:

• animals

• plants

• examples of the diffusion of named substances.

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Extra space _____________________________________________________________

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(Total 6 marks)

Some students set up the equipment below to investigate osmosis.

8.

(a) What is osmosis?

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(3)

(b) (i) What will happen to the water level in the capillary tube during the investigationbecause of osmosis?

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(1)

(ii) Use your knowledge of osmosis to explain why this happens.

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(2)

(Total 6 marks)


Plant roots absorb water from the soil by osmosis.

(a) What is osmosis?

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(3)

9.

(b) The image below shows part of a plant root.

The plant root is adapted for absorbing water from the soil.

Use information from the diagram to explain how this plant root is adapted for absorbingwater.

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(3)

(Total 6 marks)


The image below shows an epithelial cell from the lining of the small intestine.

(a) (i) In the image above, the part of the cell labelled A contains chromosomes.

What is the name of part A?

______________________________________________________________

(1)

10.

(ii) How are most soluble food molecules absorbed into the epithelial cells of thesmall intestine?

Draw a ring around the correct answer.

diffusion osmosis respiration

(1)

(b) Suggest how the highly folded cell surface helps the epithelial cell to absorb soluble food.

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(1)

(c) Epithelial cells also carry out active transport.

(i) Name one food molecule absorbed into epithelial cells by active transport.

______________________________________________________________

(1)


(ii) Why is it necessary to absorb some food molecules by active transport?

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(1)

(ii) Suggest why epithelial cells have many mitochondria.

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(2)

(d) Some plants also carry out active transport.

Give one substance that plants absorb by active transport.

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(1)

(Total 8 marks)

Cells, tissues and organs are adapted to take in different substances and get rid of differentsubstances.

The table shows the concentration of four ions outside cells and inside cells.

IonConcentration outsidecells in mmol per dm3

Concentration inside cellsin mmol per dm3

Sodium 140 9

Potassium 7 138

Calcium 2 27

Chloride 118 3

11.

(a) Use information from the table above to complete the following sentences.

Sodium ions will move into cells by the process

of __________________________________ .

Potassium ions will move into cells by the process

of __________________________________ .

(2)


(b) Some students investigated the effect of the different concentrations of sugar in four drinks,A, B, C and D, on the movement of water across a partially permeable membrane.

The students:

• made four bags from artificial partially permeable membrane

• put equal volumes of 5% sugar solution in each bag

• weighed each bag containing the sugar solution

• placed one bag in each of the drinks, A, B, C and D

• after 20 minutes removed the bags containing the sugar solution and weighed themagain.

The diagram below shows how they set up the investigation.

(i) The bag in drink A got heavier after 20 minutes.

Explain why.

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(3)


(ii) In which drink, A, B, C or D, would you expect the bag to show the smallest change inmass?

Tick (✔) one box.

A B C D

(1)

(iii) Explain why you think the bag you chose in part (b)(ii) would show the smallestchange.

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______________________________________________________________

(2)

(Total 8 marks)

The image below shows some muscle cells from the wall of the stomach, as seen through a lightmicroscope.

12.

(a) Describe the function of muscle cells in the wall of the stomach.

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(2)


(b) The figure above is highly magnified.

The scale bar in the figure above represents 0.1 mm.

Use a ruler to measure the length of the scale bar and then calculate the magnification ofthe figure above.

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Magnification = _______________ times

(2)

(c) The muscle cells in Figure above contain many mitochondria.

What is the function of mitochondria?

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(2)

(d) The muscle cells also contain many ribosomes. The ribosomes cannot be seen in thefigure above.

(i) What is the function of a ribosome?

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(1)

(ii) Suggest why the ribosomes cannot be seen through a light microscope.

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(1)

(Total 8 marks)


This question is about cell structures.

(a) Draw one line from each cell structure to the type of cell where the structure is found.

Cell Structure Type of cell where the

structure is found

Nucleus Prokaryotic cells

Permanent vacuole Plant cells only

Plasmid Eukaryotic cells

(2)

13.


(b) Figure 1 shows a plant cell.

Figure 1

What are the names of structures A, B and C?

Tick one box.

Structure A Structure B Structure C

Chloroplast Vacuole Cell wall

Nucleus Chloroplast Cell membrane

Vacuole Mitochondrion Cell membrane

Vacuole Ribosome Cell wall

(1)

A student observed slides of onion cells using a microscope.

Figure 2 shows two of the slides the student observed.

Figure 2

The cells on the slides are not clear to see.


(c) Describe how the student should adjust the microscope to see the cells on Slide A moreclearly.

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(1)

(d) Describe how the student should adjust the microscope to see the cells on Slide B moreclearly.

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(2)

(e) The student made the necessary adjustments to get a clear image.

Figure 3 shows the student’s drawing of one of the cells.

Figure 3

The real length of the cell was 280 micrometres (µm).

Calculate the magnification of the drawing.

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Magnification = × _________________________

(3)

(Total 9 marks)


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